Power Semiconductor Devices and Their Applications MCQs

Question 1

Staticinduction thyristors have

Accepted Answer

high dv / dt and high di / dt

Answer

high dv / dt and low di / dt

Answer

low dv / dt and high di / dt

Answer

low dv / dt and low di / dt

Question 2

MOS controlled thyristors have 1. Low forward voltag drop during conduction 2. Fast turn-on and turn-off time 3. Low switching losses 4. High reverse voltage blocking capability 5. Low gate input impedance of these statements

Accepted Answer

1,2 and 3 are correct

Answer

3,4 and 5 are correct

Answer

2,3 and 4 are correct

Answer

1, 3 and 5 are correct

Question 3

For a sinusoidal input voltage Vs = Vm sin cot = J5.T Vs sin cot If the input voltage is connected to load for n cycles and is disconnected for m cycles, the rms output voltage is given by Vo = Vs IF( where duty cycle K is given by

Accepted Answer

n/(m + n)

Answer

m+n

Answer

m ? n

Answer

mn

Question 4

A SCHOTTICY diode is a

Accepted Answer

majority carrier device

Answer

minority carrier device

Answer

fast recovery diode

Answer

both a majority and a minority carrier diode

Question 5

Optocouplers combine

Accepted Answer

Cuk regulator

Answer

Buck regulator

Answer

Boost regulator

Answer

Buck-boost regulator

Question 6

Which of the following statements are correct? 1. BJTs have positive temperature coefficient 2. Diodes are connected in series to increase the capability 3. The input power factor of controllers, which varies with delay angle, is generally poor, especially at the low output range of these statements

Accepted Answer

2 and 3 only

Answer

1 and 2 only

Answer

1 and 3 only

Answer

1, 2 and 3

Question 7

Inverter gain is given by the ratio

Accepted Answer

ac output voltage dc input voltage

Answer

dc output voltage ac input voltage

Answer

ac output voltage ac input voltage

Answer

dc output voltage dc input voltage

Question 8

In resonant pulse inverters

Accepted Answer

dc saturation of transformer core is minimised

Answer

dc output voltage variation is wide

Answer

the frequency is low

Answer

the output voltage is never sinusoidal

Question 9

The efficiency of a expected in the range

Accepted Answer

92 to 999 percent

Answer

50 to 55 percent

Answer

65 to 72 percent

Answer

82 to 87 percent